Woven fiber bodies (carbon-fiber fabrics) formed from a plurality of carbon fiber filaments bundled using a sizing agent and woven as warp and weft threads (the bundles hereinafter referred to as “fiber bundles” or simply “threads”), or unidirectional fiber bodies having such threads arranged in one direction, are, e.g., uniformly impregnated with epoxy resin or the like to form a prepreg. A plurality of such prepregs are laminated and cured to form lightweight, high-strength composite materials; therefore, composite materials made of carbon fiber fabric in particular are widely used in aircraft materials, automotive applications, and other fields.
Prepreg manufacturing methods that have been commonly used in recent years include a “hot-melt” method in which a resin sheet formed by laminating a thermosetting resin on a release film is layered on one or both sides of a fiber body and heated/pressed while the fiber body is continuously conveyed along a guide, whereby the fiber body is impregnated with the resin, as disclosed in Patent Documents 1 and 2, for example.
In the hot-melt method, the resin sheet is manufactured by a separate process and wound onto a winding roll in the same manner as the fiber body, and the fiber body can be impregnated with the resin merely by unrolling the fiber body and the resin sheet from the respective winding rolls or the like thereof, and laminating and heating for impregnation. The hot-melt method therefore requires only a small number of steps using simple equipment.    [Patent Document 1] Japanese Laid-open Patent Publication No. 11-309716    [Patent Document 2] Japanese Laid-open Patent Publication No. 2003-138041